Biocompatible oral bandage, application and method of manufacture

ABSTRACT

Biocompatible adhesive protective dressings, and methods of manufacturing and using the same, having properties suitable for use on moist tissues such as gingiva. The dressing may include a flexible sheet, e.g. a metal foil, with an irradiated gamma radiation sensitive adhesive on one surface. The properties of gamma sensitive adhesives are modified by exposure to gamma radiation so as to increase their adhesiveness and volume. The dressing may be applied to human or animal tissue to protect the tissue from the environment, and retain autogenous and other substances at the application site. The dressing may be used at surgical sites or wounds.

This is a division of application Ser. No. 09/641,077, filed Aug. 17,2000, now U.S. Pat. No. 6,492,573, issued Dec. 10, 2002. Each of theseprior applications is hereby incorporated herein by reference, in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention pertains to protective dressings, and more particularly toadhesive protective dressings that may be used with animal or humantissue to promote healing, particularly of an oral cavity wound orsurgical site.

2. Description of Related Art

It is generally desirable to protect wounded human or animal tissues,particularly oral tissue after gingival surgery, e.g., after toothextraction. A recent surgical site or wound, in addition to beinguncomfortable or painful, is susceptible to infection. Further, lingualand masticatory action, saliva and fluid flow, and food and debrisentering an oral wound can delay clotting or dislodge a clot andinterfere with healing.

Typically, after oral surgery the surgical incision is often sutured anda cotton dressing (gauze) or a periodontal pack is placed on thesurgical site. The dressing's primary purposes are to apply pressure tothe wound to help stop bleeding, provide some protection againstcontaminants, and act as temporary physical barrier to the oralenvironment. However, a dressing that is made of an absorbent material,such as cotton or the like, has limited ability to prevent moisture andsaliva from reaching the surgical site and itself may become saturated,rendering it useless. Moreover, the dressing is held in place by eithercompression by the patient, e.g., biting down, or by wedging the packbetween adjacent teeth. These methods do not reliably hold the dressingin place and it may be dislodged by lingual and masticatory action, andin any event, does not provide an adequate seal to prevent particlesand/or moisture, e.g., saliva, from reaching the site. Such a dressingis only effectively used for perhaps a few hours after surgery.

It would be desirable to use a dressing that would prevent moisture fromreaching a surgical site or wound, adequately seal the site from theenvironment, be pliable and imporous, and be sufficiently adhesive tothe site to be reliably retained to it for sufficient time to allowhealing to begin without interference from the oral environment. Incases where the wound or surgical site has been sutured, the patientalso may need to return to the surgeon's office at a later date to havethem removed.

Numerous materials are known that are both moisture proof, imporous andbiocompatible, so as not to not cause physical or chemical damage to thetissues. Such materials include, for example, metals, plastics, vinyls,and hydrogels. These materials are also available in pliable form, e.g.,metal foil, such as tin or aluminum. Biocompatible adhesives are alsoknown and include waxes, powders, gums, polymers (such as acrylics) andother materials.

U.S. Pat. No. 1,550,425 to Burlew, which is hereby incorporated byreference in its entirety, describes an adhesive covering for protectingdental fillings in teeth from moisture. The covering consists of a thinmetal foil upon which is deposited a film or layer of paraffin that isunited to the foil by heat so as to resist separation. On the outersurface of the paraffin there is rolled or pressed a coating of finelyground gum tragacanth. Jelenko Company of Armonk, N.Y. sells such acovering as Burlew™ Dryfoil™ and Burlew™ Orthofoil™. In particular, theJelenko product is 99.8% tin foil. The Dryfoil™ has a thickness of about0.00075 inches, while the Orthofoil™ has a thickness of about 0.0013inches. The slightly adhesive wax/powder surface allows the foil toadhere to dried teeth.

However, the Burlew covering possesses insufficient adhesiveness toadhere to gingival tissue, which is moist, and its limited thicknessprovides only minimal physical protection. In addition, it is notsterile, and thus not suitable for post-surgery wound protection.

Thus, it would be desirable for such a covering to have increasedcapability to seal protected tissues from the oral environment andincreased adhesiveness for retention. It would also be desirable toprovide the tissue with increased physical protection of the tissue. Itwould further be desirable that such a covering would be sterile. Inaddition, it would be desirable to reduce or eliminate the need forsuturing a wound or surgical site.

SUMMARY OF THE INVENTION

The present invention is directed to providing an adhesive dressing,particularly a gingival protectant having the aforementioned desirableproperties.

The invention is a biocompatible adhesive protectant covering or bandagefor use with human or animal tissues, and methods of producing the same.The invention comprises a flexible, pliable, ductile, imporous,moisture-proof, i.e., impervious to moisture, dressing with an adhesivefor adhering the covering to tissues for temporary retention andprotection from moisture. The adhesive is suitable for both hard andsoft tissues, including moist gingival tissues in the mouth, as opposedto merely hard tissues. The protective covering is preferably easilyapplied to the tissues and occupies minimal space, which is beneficialin the mouth, allowing it to be opened and closed with ease whileeffectively preventing contact of the tongue or lips with the tissue.The dressing may be configured so as to be placed upon a surgical siteor wound.

The adhesive may comprise a gamma radiation sensitive adhesive. When theadhesive is gamma irradiated or otherwise exposed to gamma radiation,i.e., above normal background radiation levels, it undergoes physicaland chemical changes. These changes include an increase in volume andadhesiveness. The degree of increased volume and adhesiveness, ortackiness, increases with increased irradiation. The amount ofirradiation of the adhesive protective covering may be varied dependingupon the amount of volume increase and adhesiveness desired. Theirradiated adhesive may then be applied to tissue and adhere to it, andwhen utilized with a protective covering or “oral bandage,” adhere thecovering to the tissue. The increased volume and tackiness may assistthe covering in preventing undesirable environmental elements, e.g., inthe mouth, from reaching the tissue, and cushioning and/or protectingthe tissue from physical impact and contaminants.

The adhesive may be irradiated to a degree so that it will adhere to thetissue for a sufficient time for the tissue to significantly heal. Thisincludes moist tissues that are subject to mechanical forces. Thus, theadhesive, alone or in combination with a protective covering, protectsthe tissue to promote healing and to minimize the possibility of bloodclot breakdown, infection, or contamination, all of which may result inpain and discomfort.

Gamma radiation may also sterilize the adhesive and protective covering,thereby further decreasing the possibility of infection. When sterilizedin sealed packaging, the sterility may be maintained until use, whichmay be years later.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will be morereadily apparent from the following detailed description and drawings ofan illustrative embodiment of the invention where like reference numbersrefer to similar elements throughout the several views and in which:

FIG. 1 shows a partially cutaway plan view of an adhesive dressingaccording to an embodiment of the invention;

FIG. 2 shows a schematic representation of adhesive dressings in sterileblister packaging according to an embodiment of the invention;

FIG. 3 shows a schematic representation of a portion of a jaw with atooth extraction socket;

FIGS. 4a and 4 b show schematic representations of the jaw of FIG. 3that has been prepared for application of a dressing according toembodiments of the invention;

FIGS. 5a and 5 b show schematic representations of the jaws of FIGS. 4aand 4 b, respectively, with a dressing applied according to embodimentsof the invention; and

FIG. 6 shows a schematic representations of the jaw of FIG. 3 in whichan implant has been installed in an extraction socket according to anembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, a wound or surgical protective dressing 1 comprisesan adhesive 2 placed on a covering material 3 that may act as aprotective covering or bandage, such as, by way of example cloth, vinyl,metal foil, plastic, or hydrogel. The covering material 3 may may becuttable or reshapeable for any desired configuration, preferablyyieldable under finger pressure. Although the dressing 1 is shown asbeing sheet-like in shape, it may be provided in any desired shape, forexample, a strip or as a roll.

Preferably, the covering material 3 is selected to provide desiredprotective characteristics. For example, if it is desired to limit theamount of moisture reaching the covered tissue, a water-resistant,waterproof or imporous material may be used, such as, for example, afoil, plastic, vinyl or hydrogel.

The adhesive may be any biocompatible adhesive having characteristicssuitable for adhering the protective dressing to the tissue. In oneembodiment of the invention, the adhesive comprises the wax/powderadhesive of the Jelenko product described above, which may be gammairradiated to alter its physical and/or chemical characteristics. Theadhesive may be gamma irradiated (by any means) sufficient to cause thedesired property alteration, such as by a Cobalt-60 source. Thoseskilled in the art will recognize that if the protective covering is tobe irradiated along with the adhesive, e.g., during sterilization, itshould be of suitable material to perform its protective functionthereafter. In other words, those skilled in the art will be able toselect a covering whose functioning is not impaired, i.e., will notdeteriorate, upon exposure to the gamma radiation. An examples ofwater-resistant and imporous coverings that are not adversely affectedby gamma radiation are metal foils, such as tin or aluminum.

Referring now to FIG. 2, the one or more dressings 1, 8 may be placed inpackaging 4, e.g., conventional medical blister packaging, which may besealed by seals 5, preferably hermetic seals. Although the packagingshown includes six dressings, it will be understood that the packagingcan include any number of dressings of any size or combination of sizes.Preferably, each dressing is individually sealed so that one dressingmay be removed from the packaging 4 at a time without contaminatingother dressings. To this end, the packaging 4 may be provided withperforations 6 or the like to facilitate separation and removal of asingle dressing.

The dressings 1, 8, along with the packaging 4, may be gamma irradiated,which preferably, along with its seals 5, is not adversely affected bythe radiation. The radiation permanently alters properties of theadhesive, such as adhesiveness and volume. The dressing may beirradiated to the degree necessary to achieve the desired adhesiveness,tackiness and volume increase depending upon the application. Thoseskilled in the art will recognize that the desired adhesiveness orvolume depends upon various factors, including, but not limited to, thetissue upon which the adhesive protectant will be used, the location ofthe tissue on or in the body, the type of injury or surgery to thetissue, the environment from which the tissue is to be protected, thedegree of protection against the environmental factors desired, the typeof protective covering to be used, if any, and the length of time forwhich the adhesive is required to perform its function, e.g., adhere thedressing (bandage) to the tissue. Those in the field will be able toassess the various factors and irradiate the adhesive to obtain thedesired characteristics. By way of example, irradiation of the adhesivewith at least about 25 kGy of gamma radiation achieves an increase inadhesiveness and volume so as to adequately adhere to and protectsurgical tissues from moisture in the mouth, e.g., gum or gingivaltissue.

In certain embodiments of the invention, the adhesive, along with anyprotective covering, is sterilized. Preferably, the adhesive andcovering are gamma irradiated with at least about 25 kGy, and morepreferably between about 25 kGy and 50 kGy. In FIG. 2, where theprotective dressings 1, 8 are sealed in the packaging 4 prior toirradiation, sterilization also sterilizes the packaging, so thatsterility of the dressing is maintained until the packaging is openedfor use.

Referring now also to FIG. 3, a jaw 10 containing teeth 11, 12 has had atooth (not shown) extracted, leaving an extraction site 13 with anextraction socket 14, which may be generally conical in shape, in thejaw bone 15 below the gum tissue 16. Although an extraction site isshown for a tooth having only one root, i.e., a bicuspid, those skilledin the art will understand that the invention may be utilized on anyextraction site within the mouth, including teeth having two, three orfour roots. After extraction, the jaw bone 15 and incised gum tissue 16are exposed to the environment in the mouth, which in addition topossibly causing pain to the patient, can lead to infection and debrisin the extraction site and thereby delaying or preventing healing.

In order to place a dressing upon the surgical site or wound, a portion7 of the blister packaging 4 is opened and an irradiated adhesivedressing 8, preferably sterilized (e.g., with between 25 and 55 kGY ofgamma irradiation), is removed. In this manner, the other dressings,e.g., 1, in the packaging 4, remain sealed and sterilized.

Referring to FIGS. 4a, 4 b, 5 a, and 5 b, the dressing 8 may be trimmedto a desired size and shape, preferably matching the contours anddimensions of the area to be covered, e.g., the gingival tissue at andadjacent to the wound site. It is also preferable that the dressing notoverly interfere with oral function, e.g., speaking. For example, inFIG. 4a, the dressing 8 may be trimmed to have contoured lateral edges17 a, 17 b so that the dressing 8 fits between the adjacent teeth 11, 12and generally follows the contours 18, 19 of the teeth 11, 12 andgingival tissue 16 adjacent to the extraction site 13, i.e., thedressing 8 contacts soft tissue, e.g., gingiva, only. In the embodimentshown in FIG. 4b, protective dressing 20, whose composition may besimilar to dressing 8, has a contoured edge 17 c so as to generallyfollow the contour 18 of tooth 11, but the other lateral edge 17 d ofthe dressing 20 has not been contoured or trimmed and may overlapadjacent, e.g., one or two, teeth. Alternatively, the dressing may notbe trimmed or multiple dressings may be used.

In order to place the dressing 8, 20 on the extraction site 13, thedressing 8, 20 is positioned over the extraction site 13 with theadhesive 2 facing toward the soft tissue. The dressing 8, 20 is appliedagainst the gum tissue 16, preferably on the buccal and lingual sides.It may also extend over adjacent teeth, e.g., 12, if desired by thesurgeon or operating nurse.

Preferably, the dressing 8, 20 is applied to the jaw 10 to provideoptimum protection to the surgical site 13, i.e., to isolate thesurgical site from the oral environment. For example, dressing 8 may beconfigured upon placement so that a portion 21 of the dressing 8, 20 isapplied to the buccal side 22 of the jaw 10, and another portion 23 ofthe dressing is applied to the lingual side 24 of the jaw 10 (FIGS. 5a,5 b). In addition, in embodiments where the dressing overlaps adjacentteeth, as in FIGS. 4b and 5 b, the overlapping portion 25 of thedressing 20 is configured to generally conform to the shape of tooth 12.Also preferably, the adhesive 2 may be distributed on the area so thatif assists the covering 3 in sealing the site 13 from the oralenvironment.

Further, in a preferred method of applying the dressing, before thedressing is applied, the gingiva 16 surrounding the extraction site 13is dried in order to increase initial adhesion of the dressing to thegum 16. This may be accomplished with cotton swabs and/or air, e.g.,compressed air. This drying may assist in accurate placement of thedressing on the jaw 10. Also, for certain types of adhesives, forexample, waxes and powders, the adhesive 2 is preferably moistenedbefore application, e.g., with water or sterile saline so as to aidinitial adhesion and placement.

With the adhesive dressing applied to the surgical site or wound,saliva, food, and oral debris are prevented from reaching the gingivaltissue. It is also protected from masticatory and lingual tongue actionwhile healing occurs. The adhesive protective dressing also helps retainblood at the surgical site, which clots and helps to stop bleeding, thusreducing or eliminating the need for suturing the gum tissue. Autogenousbone cells, present in the retained blood from the marrow at the socketperiphery, clot and assist in regeneration of bone. The adhesivecovering helps prevent this beneficial blood material from beingdislodged, broken down, or washed away in the oral environment. Thisclot protection also occurs when a bone graft material, e.g., Bioplant®HTR®, available from Bioplant, Inc. of South Norwalk, Conn. has beenmixed with the bleeding marrow and placed into the extraction socket, asdescribed below.

The dressing 8, 20 may be left on the gum tissue until sufficienthealing has occurred, which may be up to seven days or longer, andpreferably is about one day to one week. If necessary, adhesiveretention of the dressing 8, 20 may be aided by use of a periodontal gumpack 26 (FIGS. 5a & 5 b). The periodontal pack 26 may be an absorbent,e.g. cotton, material. It may be placed over the dressing 8, 20 so thatthe periodontal pack 26 is held in place by the wedging action ofadjacent teeth 11, 12, e.g., by wedging the pack 26 between the teeth11, 12.

Preferably, the adhesive's characteristics allow the dressing to beremoved from the surgical site without excessive difficulty and anyadhesive remaining on the tissues also may be removed. For example, theadhesive disclosed by Burlew, either in irradiated or non-irradiatedstate, permits the dressing to be removed from the site without tearingof the dressing or excessive pulling on the tissues, blood clot/graftmaterial, or implant, which can cause pain or damage. Any adhesiveremaining on the tissues may be removed mechanically, e.g., gentlescraping, or will be removed by natural oral function, e.g., naturalsaliva flow, eating, drinking, and/or lingual action (speaking). As willbe recognized by those skilled in the art, there afre various knownbiocompatible adhesives exhibiting such properties, e.g., water-solublewaxes and gums such as gum tragacanth.

Although the above describes one method of utilizing the invention at awound or surgical site, those skilled in the art will recognize thatmany variations on the above technique are contemplated by theinvention. For example, as shown in FIG. 6, at the tooth extraction site13 or other site where bone tissue is affected, bleeding marrow may becollected and mixed with graft material 27, e.g., form a paste. Thispaste may then be placed onto the bone, e.g., in the extraction socket14. The graft material or paste 27 is, preferably, at least in part,retained by the dressing 8, 20, which is placed over the tissue asearlier described. The blood/graft mixture or paste promotes clotting,healing, and bone regeneration.

The invention contemplates that any suitable graft material may beutilized with a bone tissue wound or surgical site, as would be known tothose in art. Examples of such graft material include, but are notlimited to, autogenous (from the surgical site or other hard tissue ofthe patient), xenograft (e.g., bovine), allograft (human derivatives),and alloplast (e.g., ceramic or plastic) materials. Various alloplastmaterials are disclosed in U.S. Pat. No. 4,536,158 to Bruins and Ashman;and U.S. Pat. Nos. 4,535,485, 4,547,390 and 4,728,570 to Ashman et al.,which cover the Bioplant® HTR® material described above. Theaforementioned patents are incorporated herein in their entirety.

Referring again to FIG. 6, in yet other embodiments of the invention,the adhesive protective dressing 8 is placed over the site of a recentlyinstalled dental implant 28. Dental implants are well-known in the artand may be installed into the edentulous area of a patient's jaw bone toanchor a prosthesis. It is also known that an implant may be installedimmediately after a tooth extraction in order to avoid later invasiveprocedures, which may require removal of bone that has regrown, and toprevent bone resorption at the extraction site, which commonly occursafter tooth extraction. Although FIG. 6 shows a submergible threadedcylinder-type implant, it will be understood that any type of suitableimplant may be used, which may be selected for, among other reasons, thelocation of the extraction and the profile and condition of theanchoring bone. Generally, extraction sockets tend to be conical inshape, and preferably, cylindrical-type implants, or more preferably,conical or U-shaped implants, such as those disclosed in U.S. Pat. No.4,521,192 of L. I. Linkow, U.S. Pat. No. 2,609,604 of B. F. Sprague, andSer. No. 09/248,079 of Ashman et al. which are incorporated by referencein their entirety, may be utilized in order to more closely fit thedimensions of the extraction site. In addition, the area around theimplant 28 in the extraction socket 14 may be backfilled with the bonegraft material mixture 27 to promote bone regrowth, as described above,which assists in retaining the implant 28.

Once the implant 28 is installed in the bone, the dressing 8 may beapplied to the extraction/implant site 13 in the manner discussed above.The dressing 8 retains the bone graft material mixture 27 and blood atthe extraction/implant site 13, and protects it from the oralenvironment. Due to the retentive/protective properties of the dressing8, the suturing of the gum or gingival tissue 16 normally required afterimplant installation in a two-stage or a single-stage implant proceduremay be avoided or minimized. By way of example, the protective adhesivebandage may be utilized alone, i.e., without sutures, or in addition tosutures to further protect the surgical area. This may reduce oreliminate the need to have to later reopen the gum 16 to install anabutment or other prosthetic component onto the implant 28, resulting inless surgical trauma to the patient.

Those skilled in the art will recognize that the materials and methodsof the present invention will have various other uses in addition to theabove described embodiments. They will appreciate that the foregoingspecification and accompanying drawings are set forth by way ofillustration and not limitation of the invention. It will further beappreciated that various modifications and changes may be made thereinwithout departing from the spirit and scope of the present invention,which is to be limited solely by the scope of the appended claims.

What is claimed is:
 1. A sterile surgical package comprising at leastone sterilizible protective dressing sealed in sterilizible medicalpackaging, said at least one sterilizible protective dressing comprisinga sterilizible covering material and a gamma radiation sensitiveadhesive alterable in at least one characteristic other than sterilitythereby located on one side of said covering material, said packagehaving been sterilized with gamma radiation in an amount sufficient toalter said at least one characteristic.
 2. The package of claim 1,wherein each of said at least one sterilizible protective dressing isseparately sealed in said sterilizible medical packaging.
 3. The packageof claim 1 sterilized with at least about 25 kGy of gamma radiation. 4.The package of claim 1, wherein said at least one characteristicincludes adhesiveness.
 5. A method of providing a sterile protectiveadhesive dressing comprising the steps of: providing at least onesterilizible protective dressing sealed in sterilizible medicalpackaging, said at least one sterilizible protective dressing comprisinga sterilizible covering material and gamma radiation sensitive adhesivealterable in at least one characteristic other than sterility thereby onone side of said sterilizible covering material; and sterilizing said atleast one sterilizible protective dressing with gamma radiation in anamount sufficient to alter said at least one characteristic.
 6. Themethod of claim 5, wherein each of at least one sterilizible protectivedressing is separately sealed in said sterilizible medical packaging. 7.The package of claim 5 sterilized with at least about 25 kGy of gammaradiation.
 8. The package of claim 5, wherein said at least onecharacteristic includes adhesiveness.